Pump, in particular a blood pump

ABSTRACT

The application relates to a pump, in particular blood pump. The pump comprises a drive shaft (3) which runs in an axial direction, a delivery element (6) which is connected to the drive shaft (3) in a distal region of this, and a housing (5) which surrounds the delivery element (6). The delivery element (6) and the housing (5) are designed in a manner such that these automatically unfold after a forced compression. The housing (5) moreover comprises an inlet region (22) with at least one inlet opening (23), a fluid-tight region (20) which surrounds a region of the delivery element (6), and an outlet region (24) with at least one opening (23) for the exit of the pump medium. The delivery element (6) is arranged in a manner such that it projects into the outlet region (24).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a United States National Stage filing under 35U.S.C. § 371 of International Application No. PCT/EP2016/073702, filedOct. 4, 2016, which claims the benefit of European Patent ApplicationNo. 15189241.1, filed Oct. 9, 2015, the contents of all of which areincorporated by reference herein in their entirety. InternationalApplication No. PCT/EP2016/073702 was published under PCT Article 21(2)in English.

The application relates to a pump, in particular to a blood pump,according to the preamble of claim 1.

Blood pumps with a proximal and a distal end as well as with a catheterwhich is arranged therebetween, and in which pumps a flexible driveshaft is guided in an interior of the catheter, are known from the stateof the art. Such blood pumps at their distal end typically comprise apump head which comprises a foldable housing and a foldable deliveryelement, wherein the delivery element is connected to a distal region ofthe drive shaft. Such pump heads can be led to locations which aredifficult to access. For example, such a pump head can be insertedthrough the femoral artery, via the aortic arch, into a region of theaortic valve of a patient, in order there to deliver blood from the leftventricle of the heart into the aorta. The drive shaft is driven at theproximal end of the blood pump by way of a motor which is typicallylocated outside the body of the patient. Such a blood pump is describedfor example in the document EP 2 868 331 A2.

It is the object of the invention to suggest an improved pump, inparticular an improved blood pump, which is more efficient in operation.

This object is achieved by a pump with the features of the main claim.Advantageous further developments are derivable from the features of thedependent claims and of the embodiment examples.

The suggested pump, in particular blood pump, comprises a drive shaftwhich runs in an axial direction, a delivery element which is connectedto the drive shaft in the distal region of this, and a housing whichsurrounds the delivery element. The delivery element and the housing aredesigned in a manner such that these automatically unfold after a forcedcompression. The housing moreover comprises an inlet region with atleast one inlet opening, a fluid-tight region which surrounds a regionof the delivery element, and an outlet region with at least one openingfor the exit of a pump medium. The delivery element is arranged in amanner such that it projects into the outlet region.

In particular, one can envisage the delivery element being arranged in amanner in which it projects into the outlet region in an expandedcondition of the housing and of the delivery element. The outlet regionsurrounds a region of the delivery element which is arranged in thedelivery direction. Due to the at least one opening of the outletregion, the delivery element is not completely enclosed in a fluid-tightmanner in the outlet region. The outlet region can hence surround aregion of the delivery element which is situated at an end of thedelivery element which points in the delivery direction. The fluid-tightregion typically connects to an end of the inlet region which issituated in the delivery direction, and the outlet region typicallyconnects to an end of the fluid-tight region which is situated in thedelivery direction. The inlet region, the fluid-tight region and theoutlet region, at least in some portions, typically have an essentiallyannulus-shaped cross section. One envisages the pump medium flowingthrough the inlet region into the housing and leaving the housing viathe outlet region on operation of the pump.

Typically in the outlet region, the housing comprises lateral openingsadditionally to the axial openings, so that a delivered pump medium, inthe outlet region, can flow out of the housing in the radial direction,or perpendicularly to the drive shaft axis, or has at least a radialspeed component when flowing out.

Surprisingly, it has been found that the pump output can be drasticallyincreased by way of such an arrangement, compared to known blood pumpsof the type described above. Given an equal motor power for example, afluid volume which is delivered in a given time interval can beincreased by up to 50% in this manner.

Typically, the delivery element here projects partly out of thefluid-tight region. The delivery element then projects partly into theoutlet region.

For example, one can envisage the outlet region overlapping an axialextension of the delivery element by at least 5%, preferably by at least10%, particularly preferably by at least 25%.

Moreover, one can envisage the outlet region overlapping an axialextension of the delivery element by 75% at the most, preferably by 65%at the most, particularly preferably by 50% at the most.

The housing typically comprises a lattice, in particular in the outletregion. The lattice can comprise a shape memory material or a suitablememory alloy, so that the lattice can be reliably expanded andcompressed. The lattice can comprise for example nitinol, a plastic, aniron alloy or a copper alloy. One can envisage the housing comprising alattice in the inlet region and/or in the fluid-tight region and/or inthe outlet region.

Typically, the housing comprises an elastic covering. The elasticcovering can be arranged for example on an inner side and/or an outerside of a possibly present lattice. A covering is suitable for closinglattice openings, and may be, for example, a polyurethane covering.However, for example polyethylene, polypropylene, silicone or parylenescan also be used.

The fluid-tight region can be formed at least partly by way of theelastic covering. The outlet region and the inlet region are typicallyformed by the lattice with its lattice openings, whereas the fluid tightregion between the outlet region and the inlet region is formed by acovering of the lattice by the elastic covering.

In the expanded condition, one can envisage the housing having a conicalsection tapering conically in the delivery direction, in the outletregion. In its expanded condition, one can also envisage the housinghaving a conical section widening in the delivery direction, in theinlet region.

In an expanded condition, the housing can moreover comprise anessentially tubular section in the outlet region, said section beingconnected to the conical section at an end which is situated in thedelivery direction. The tubular section of the outlet region can mergeinto a tubular section of the fluid-tight region at an end which isopposite to the delivery direction.

Typically, the lattice has larger lattice openings in the outlet regionthan in the fluid-tight region. Moreover, one can envisage the latticecomprising larger lattice openings in the inlet region than in thefluid-tight region. Damage to the blood due to the pump can be preventedor at least minimised by way of an enlargement of the openings in theregions of the housing which are subjected to through-flow.

One can envisage a region of the outlet region being surrounded by anoutflow element. In particular, one can envisage a region of the outletregion being surrounded by an outflow shield which extends from the pumphousing in the delivery direction. This outflow shield can essentiallyhave a shape which corresponds to a lateral surface of a truncated cone.Typically, a tapered end of the outflow shield is fastened to thehousing, in particular in the fluid-tight region. A widening end of theoutflow shield can be aligned in the delivery direction, so that theoutflow shield partly or completely encloses the outlet region. The flowconditions in the pump can be further optimised by the outflow shield,by which means the delivery output can be improved.

It is also possible for a region of the outlet region to be surroundedby an outflow tube which extends from the pump housing in the deliverydirection. Typically, the outflow tube is designed in such a flexiblemanner that it forms a check valve. Such an outflow tube, similarly tothe outflow shield, can contribute to a further optimisation of the flowconditions and to an improvement of the pump output. For example, anoutflow tube as is described in the document EP 2 345 440 B1 ispossible.

Typically, the inlet region does not overlap with an axial extension ofthe delivery element. The delivery element can therefore be arranged ina manner such that this does not project into the inlet region. Ashielding of the delivery element from parts of the body of a patientcan be achieved in a suction region of the pump by way of this, by whichmeans an injury to the patient can be avoided.

The drive shaft is typically connected to a motor for driving the driveshaft, at a proximal end of the drive shaft. The shaft can be forexample a flexible shaft which is guided in a catheter.

The pump can be configured for pumping blood from a ventricle into ablood vessel of a patient, wherein the drive shaft, in a proximalregion, is configured for connection to a motor which is outside a bodyof a patient. The motor can be designed for example for fastening to athigh of a patient. The catheter and the drive shaft can have anadequate length of at least 50 cm, preferably at least 90 cm for thispurpose. A maximal length of the flexible drive shaft can be 200 cm,preferably 150 cm.

The lattice can be designed as a rhomboid lattice with essentiallyrhomboidal lattice openings, in a region of the housing.

One can envisage the lattice comprising lattice struts, wherein a numberof the lattice struts along a periphery of the rhomboid lattice ism·2^(n), with m and n being natural numbers, preferably 32 or 40,wherein m is greater than 2, preferably greater than 3. One can alsoenvisage the housing, in the outlet region, comprising m, preferably 4or 5 lattice struts along a periphery.

Such a design permits a particularly stable reduction of the latticestruts, for example in the direction of a distal end or in the directionof a proximal end of the housing. Furthermore, a particularly stableenlargement of the lattice openings can be achieved in this manner.Here, one can envisage all lattice struts being merged in pairs in theshape of a Y along a periphery of the housing at a certain axialposition. Such a merging can be effected repeatedly at one or morefurther axial positions of the housing. Given a presence of, forexample, 5 struts and openings along the periphery of the housing, astepwise increase in the number of struts to 10, 20, 40, . . . can betherefore, for example, be effected at an end of the housing. Havingbegun, for example, with 4 (3) struts and openings along the peripheryof the housing, the number of struts and openings can also be increasedin steps to 8 (6), 16 (12), 32 (24), . . . . Here, n indicates a numberof the steps and m a number of struts and openings along a periphery ofthe housing at an axial position, at which the merging begins.

The application moreover relates to a blood pump which comprises a driveshaft running in an axial direction, a delivery element which isconnected to the drive shaft in a distal region of this, and a housingwhich surrounds the delivery element. The delivery element and thehousing are designed in a manner such that these automatically unfoldafter a forced compression. The housing comprises a lattice, an inletregion with at least one inlet opening, a fluid-tight region, whichsurrounds a region of the delivery element, and an outlet region with atleast one opening for the exit of a pump medium. The lattice moreovercomprises lattice openings and lattice struts, wherein a number of thelattice struts along a periphery of the lattice at a first axialposition of the lattice is m and wherein the lattice is designed in amanner such that the number of lattice struts along a periphery of thelattice increases in an axial direction with n steps to m·2^(n) latticestruts at a second axial position of the lattice, wherein m and n arenatural numbers and m is larger than 2, preferably larger than 3. m canbe for example 3, 4 or 5. Alternatively m can be for example 6, 8 or 10.

Typically, one envisages the number of lattice struts along theperiphery of the lattice at the second axial position of the latticebeing 32 or 40. Moreover, one typically envisages the housing comprisingm, preferably 4 or 5 lattice struts along a periphery in the outletregion. Injury to the blood when it flows through the lattice struts ofthe outlet region can be reduced by way of such an embodiment.

Embodiment examples of the invention are hereinafter described by way ofthe drawings. There are shown in:

FIG. 1 a schematic representation of a pump arrangement,

FIG. 2 a schematic representation of a pump head,

FIGS. 3(a), (b) two further schematic representations of the pump head,

FIG. 4 a schematic representation of a housing,

FIG. 5 a schematic representation of a motor and

FIG. 6 a schematic representation of a further motor.

FIG. 1 schematically shows a pump arrangement 1. The pump arrangement 1comprises a catheter 2, in which a flexible drive shaft 3 is guided. Thecatheter 2 is connected to a pump head 4. This pump head 4 comprises ahousing 5 and a delivery element 6 which is arranged in the housing 5and which can be driven via the drive shaft 3 by a motor 7 connected tothe proximal end of the drive shaft 3. The pump head 4 as well as thecatheter 2 and the drive shaft 3 are introduced into the femoral artery9 via a port 8, in a manner such that the pump head 4 in the region ofthe left ventricle 10 is located in the region of the aortic valve 11.On operation, the drive shaft 3 is driven by the motor 7 and the pumparrangement 1 delivers blood from the left ventricle 10 into the aorta12. In the shown arrangement for left heart assistance, a deliverydirection of the pump arrangement 1 corresponds to the direction from adistal end 13 of the pump arrangement 1 to a proximal end 14 of the pumparrangement 1.

However, the pump arrangement 1 can also be configured for a delivery ofblood in a direction from the proximal end 14 to the distal end 13 ofthe pump arrangement 1, which is suitable for example for right heartassistance.

The pump head 4 is represented schematically in FIG. 2 . Recurringfeatures in this and in the subsequent drawings are provided with thesame reference numerals. The pump head 4 comprises the delivery element6 and the housing 5. The delivery element 6 in the present example isdesigned as a pump rotor with two flexible segments in the form of rotorblades. Additionally, the drive shaft 3, which is mounted on a distalregion 15 of the pump head 4, is represented. A so-called pigtail 17,which is manufactured from an elastically deformable material, isprovided at the distal end 16 of the pump head 4. A cylindrical element18 is rigidly connected to the drive shaft 3. The delivery element 6 isfastened to the cylindrical element 18. The delivery element 6 as wellas the housing 5 are designed in such an unfoldable manner that they canautomatically unfold after a forced compression. The delivery element 6is manufactured from a plastic. The housing 5 is manufactured from theshape memory material nitinol. The complete pump head 4 can be unfoldeddue to the fact that the delivery element 6 as well as the housing 5 aredesigned in an unfoldable manner.

The housing 5 is designed as a rhomboidal lattice 19 and in afluid-tight region 20 comprises an elastic covering 21 of polyurethane.The elastic covering 21 covers an inner side and an outer side of therhomboidal lattice 19 in a manner such that rhomboid lattice openingswhich are formed by the lattice 19 in the fluid-tight region 20 can beclosed in a fluid-tight manner by way of the elastic covering 21.

The housing 5 moreover comprises an inlet region 22 which is not coveredby the elastic covering 21. In the inlet region 22, the rhomboid latticeopenings form inlet openings, of which one is provided, by way ofexample, with the reference numeral 23 in FIG. 2 . The housing 5moreover comprises an outlet region 24 which is likewise not covered bythe elastic covering 21. In the outlet region 24, the rhomboid-likelattice openings form outlet openings, of which one is represented byway of example and is provided with the reference numeral 25.

On operation of the pump arrangement 1, the drive shaft 3 is driven bythe motor 7, so that the delivery element 6, which is connected to thedrive shaft 3, rotates about an axis of the drive shaft 3. By way ofthis, blood is transported through the inlet openings of the inletregion 22 into the housing 5 and subsequently exits through the outletopenings of the outlet region 24, out of the housing 5. Blood isdelivered in a delivery direction 26 by way of the pump arrangement 1 inthis manner.

The elastic covering 21 does not completely surround the axial extensionof the delivery element 6. Instead, the delivery element 6 projectspartly into the outlet region 24, so that at least the outlet openingwith the reference numeral 25 is arranged laterally, i.e. in the radialdirection, next to the delivery element 6. In contrast, the elasticcovering 21 at its distal end is designed in a manner such that thedelivery element 6 does not project or does not significantly projectinto the inlet region 22 and is therefore not laterally surrounded byinlet openings.

The design of the elastic covering 21 and the delivery element 6 andtheir arrangement with respect to one another is such that roughly athird of the axial extension of the delivery element 6 is not surroundedby the elastic covering 21 which forms the fluid-tight region 20. In theshown example, the same share of the axial extension of the deliveryelement 6 is surrounded by the outlet region 24.

The pump head 4 additionally comprises an outflow element. This can bedesigned as an outflow shield 27 as is represented in FIG. 3(a), or asan outflow tube 27′ as is represented in FIG. 3(b).

The outflow shield 27, which is represented in FIG. 3(a), is fastened tothe housing 5 in the fluid-tight region 20 of the housing 5. The outflowshield 27 has the shape of a lateral surface of a truncated cone andextends in the delivery direction 26 such that this shield is widened inthe delivery direction 26. The delivery element 6 and the outlet region24 are surrounded by the outflow shield 27. In another embodiment, onecan also envisage the outlet region 24 being partly surrounded by theoutflow shield 27

The pump head 4 in FIG. 3(b) only differs from the pump head 4represented in FIG. 3(a) in that an outflow tube 27′ is provided insteadof the outflow shield 27. This outflow tube 27 is fastened to thehousing 5 in the fluid-tight region 20 and extends from there in thedelivery direction 26. The outflow tube 27′ is manufactured frompolyurethane and comprises openings 28, 28′, 28″ in a region situated inthe delivery direction 26. In the example shown, the outlet region 24 iscompletely surrounded by the outflow tube 27′. The outflow tube 27′ isflexible and closes automatically when a blood flow occurs in adirection that is opposite to the delivery direction 26, due to theoutflow tube 27′ being pressed onto the catheter 2 and/or onto thehousing 5.

FIG. 4 schematically shows the rhomboidal lattice 19 of the housing 5.The fluid-tight region 20 with the elastic covering 21 as well as theinlet region 22 and the outlet region 24 are additionally represented.Regions of the inlet region 22 and of the outlet region 24 have aconical shape, whereas the fluid-tight region 20 is essentially tubular.The lattice 19 comprises lattice struts, of which one is characterisedby way of example by the reference numeral 45. The lattice struts 45 runin a manner such that the essentially rhomboidal lattice openings arelarger in the inlet region 22 as well as in the outlet region 24 than inthe fluid-tight region 20. Lattice struts which are arranged on a sideof the housing 5 which is away from the viewer are merely represented inFIG. 4 in a dotted manner for an improved overview.

In the fluid-tight region 20, the lattice struts 45 form a comparativelyfinely meshed lattice. The lattice 19, along a peripheral of the housing5 in the fluid-tight region 20, comprises thirty-two struts or, inasmuchas the periphery is considered at an axial position of the housing 5with node points, comprises sixteen nodes. A largely round cross sectionof the housing 5 in the fluid-tight region 20 is achieved by way of sucha close-meshed lattice 19.

The number of lattice struts 45 along a periphery of the housing 5 ishalved from the fluid-tight region 20 in the direction of the inletregion 22 and in the direction of the outlet region 24 by way of mergingthe lattice struts into pairs, so that the housing 5 in thecorresponding regions comprises sixteen lattice struts 45 along theperiphery, in which no node points are present. The number of latticestruts 45 is subsequently reduced once again in the direction of theinlet region 22 and of the outlet region 24, by way of merging thelattice struts into pairs, so that the housing 5 in these regionscomprises eight lattice struts 45. A further reduction of the number oflattice struts 15 is effected in the outlet region 24 in the mannermentioned above, so that the housing 5 in a region situated further inthe delivery direction 26 has only four lattice struts 45 along aperiphery.

A lattice 19 with larger lattice openings than in the fluid-tight region20 forms in the inlet region 22 and in the outlet region 24 on accountof the described reduction of the number of lattice struts 45.

The lattice struts 45 in the conical regions of the outlet region 24 andof the inlet region 22 form a spiral-shaped structure, which leads to areliable unfolding of the pump head 4 when pushing the pump head 4 outof a cannula.

FIG. 5 shows a schematic view of the motor 7. The motor 7, in the regionof a shaft stub 29, is connected to the catheter 2, which is glued intothe shaft stub 29. The flexible drive shaft 3 is guided in the catheter2. The motor 7 moreover comprises a rotor 30, which has a rotor magnet31.

The flexible drive shaft 3 is connected to the rotor 30 in a manner suchthat given a rotation of the rotor 30, a torque is transmitted from therotor 30 to the flexible drive shaft 3. The torque is transmitted to thedelivery element 6 via the flexible drive shaft, so that the pumparrangement is driven by the motor 7.

The rotor 30 is axially mounted by way of two bearings 32, 33. One ofthese bearings 33 is biased by way of a spring element 34 for an axialstabilisation of the rotor 30. The spring element 34 can be designed,for example, as a helical spring or as an annular spring. The bearings32, 33 can each be designed as ball bearings or as plain bearings. Ifthe bearings 32, 33 are designed as ball bearings, then the bearings 32,33 comprise balls of ceramic and cages of plastic so that the ballbearings have non-magnetisable material. The rings of the bearings canbe designed for example from a magnetisable metal or from anon-magnetisable material. If the bearings 32, 33 are designed as plainbearings, then they each comprise friction partners of DLC-coatedimplant steel and yttrium-stabilised zirconium oxide.

The rotor magnet 31 comprises a biocompatible DLC coating. The motor 7moreover comprises a stator 36. The stator 36 comprises several windings37 which are connected in an electrically conductive manner toelectricity connections 38. The stator 36 moreover comprises back ironlaminations 39. The windings 37 are potted with a biocompatible epoxyresin which contains thermally conductive aluminum oxide.

A gap 40 with an annular cross section is formed between an inner sideof the coating of the windings 37 and an outer side of the coating 35 ofthe rotor magnet 31. The gap 40 has a width of 0.2 mm. This gap 40 is influid connection with a rinsing opening 41, which is connected to arinsing connection 42, wherein the rinsing connection 42 is arranged ata proximal end of the motor 7. The gap 40 is moreover in fluidconnection with an intermediate space formed between the drive shaft 3and the catheter 2. Thus, for example, a glucose solution can be rinsedthrough the rinsing opening 41 and the gap 40 and the intermediate spacevia the rinsing connection 42. Glucose solution rinses around the rotor30 during operation in this manner. A radial distance between the outerside of the rotor magnet 31 and an inner side of the windings 37 is 0.5mm. An inner radius of the windings 37 here corresponds to 1.1 times anouter radius of the rotor magnet 31.

The stator 36 and the rotor 30 are connected to one another in a mannerthat cannot be released by the user and are incorporated into a motorhousing 43. The motor housing 43 can be connected, for example, to agrip or to a cooling body. The motor can be operated in a very efficientmanner due to the small distance between the windings 37 and the rotormagnet 31, so that the motor housing 43 as well as a grip or coolingbody, which may be connected to this housing, is heated to less than 40°C. at its exposed surfaces when the pump arrangement 1 is operated at aspeed of 32,000 r.p.m and at a delivery output of 2.5 l per minute.

The motor 7′ which is represented in FIG. 6 differs from the motor 7represented in FIG. 6 merely in that the stator 36 in this embodimentcomprises a fluid-tight sleeve 44 which delimits the gap 40. In thisembodiment, the width of the gap 40 is 0.15 mm. The sleeve 44 comprisespolyether ether ketone and is magnetically inactive. The sleeve 44 isarranged in a manner such that for example the windings 37 and furtherparts of the stator 36 are separated from the rinsing fluid whichpossibly flows through the gap 40, by way of the sleeve 44. An extensionof the sleeve 44 in the axial direction is about 1.2 times an axialextension of the rotor magnet 31.

Features of the different embodiments which are merely disclosed in theembodiment examples can be combined with one another and claimedindividually.

The invention claimed is:
 1. A blood pump, comprising: a drive shaftwhich runs in an axial direction; a delivery element which is connectedto the drive shaft in a distal region of the drive shaft; and a housingwhich surrounds the delivery element, wherein the delivery element andthe housing are configured to automatically unfold after a forcedcompression, wherein the housing comprises: an inlet region with atleast one inlet opening; a fluid-tight region which surrounds a regionof the delivery element, wherein the housing comprises an elasticcovering and the fluid-tight region is formed at least partly by theelastic covering; and an outlet region with at least one opening forexit of a pump medium, wherein the delivery element comprises a rotorand the rotor is configured such that it extends into the outlet region.2. The blood pump according to claim 1, wherein the housing comprises alattice.
 3. The blood pump according to claim 2, wherein the lattice isconfigured as a rhomboid lattice with rhomboidal lattice openings, in aregion of the housing.
 4. The blood pump according to claim 3, whereinthe lattice comprises lattice struts, wherein a number of lattice strutsalong a periphery of the rhomboid lattice is m·2^(n), with m and n beingnatural numbers, wherein m is larger than
 2. 5. The blood pump accordingto claim 4, wherein the housing has m lattice struts along a peripheryin the outlet region.
 6. The blood pump according to claim 2, whereinthe lattice comprises a shape memory material.
 7. The blood pumpaccording to claim 2, wherein the lattice has larger lattice openings inthe outlet region than in the fluid-tight region.
 8. The blood pumpaccording to claim 1, wherein the outlet region of the housing comprisesa conical section tapering in a delivery direction when the housing isin an expanded condition.
 9. The blood pump according to claim 8,wherein the outlet region of the housing comprises a tubular sectionwhich is connected to the conical section at an end which is situated inthe delivery direction when the housing is in an expanded condition. 10.The blood pump according to claim 1, wherein a region of the outletregion is surrounded by an outflow tube which extends from the housingin a delivery direction.
 11. The blood pump according to claim 10,wherein the outflow tube is configured to form a check valve.
 12. Theblood pump according to claim 1, wherein the outlet region overlaps anaxial extension of the delivery element by at least 5%.
 13. The bloodpump according to claim 12, wherein the outlet region overlaps the axialextension of the delivery element by 75% at most.
 14. The blood pumpaccording to claim 1, wherein a region of the outlet region issurrounded by an outflow shield which extends from the housing in adelivery direction.
 15. The blood pump according to claim 12, whereinthe inlet region does not overlap with the axial extension of thedelivery element.
 16. The blood pump according to claim 1, wherein thedrive shaft is connected to a motor at a proximal end of the driveshaft, the motor configured to drive the drive shaft.
 17. The blood pumpaccording to claim 1, wherein the drive shaft is a flexible shaft. 18.The blood pump according to claim 1, wherein the drive shaft is guidedin a catheter.
 19. The blood pump according to claim 1, wherein theblood pump is configured to pump blood from a ventricle into a bloodvessel of a patient, wherein the drive shaft in a proximal region isconfigured for connection to a motor outside a body of the patient.